m-Chloroperbenzoic acid → 2-(4-Bromo-2,6-dichlorophenyl)-7-fluoro-2H-pyrazolo[4,3-c]pyridine 5 oxide

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Reaction Conditions

Reaction Steps

2-(4-Bromo-2,6-dichlorophenyl)-7-fluoro-2H-pyrazolo[4,3-c]pyridine (14.5 g, 40 mmol) was suspended in DCM (160 mL), at 0° C. and meta-chloroperbenzoic acid (12.4 g, 72 mmol) was added. The reaction mixture was stirred at 0° C. for 2 hours then allowed to reach room temperature and stirred overnight. Additional meta-chloroperbenzoic acid (5 g, 30 mmol) was added and the reaction mixture was stirred at room temperature for another 3 hours. The resultant mixture was quenched with saturated aqueous sodium thiosulfate solution and the layers were separated. The organic layer was washed with saturated aqueous sodium bicarbonate solution and brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was triturated with diethyl ether and the solid obtained was filtered and dried to afford the title compound as a beige solid (12.9 g, 86% yield). 1H NMR (400 MHz, DMSO-d6): δ 8.98 (d, J=2.6 Hz, 1H), 8.88 (d, J=1.4 Hz, 1H), 8.33 (dd, J=6.3, 1.5 Hz, 1H), 8.19 (s, 2H).

Provenance & Evidence